The ATmega328P prototype of the Toadstool arrived a month ago and has been through some solid testing. Here it is assembled:

I found a couple of usability issues with the physical layout which I've corrected:

• The 2x6 header for the "Toadstool Caps" (breakout boards) has been split into two 1x6 headers to add stability to the Cap
• The reset switch has been switched (!) for an SMD low profile version to prevent the Toadstool Cap from obscuring it.
• The Tantalum caps have been replaced by Aluminium ones to make the board more reflow friendly (listen to this great podcast on capacitors)
• A number of changes to silkscreen to make it more readable